INTRODUCTION TO BIOLOGY GRQ-15 PDF

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Introduction to Biology Guided Reading Question Number 15....

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UNIT 3 HUMAN IMMUNITY Guided Reading Questions Reading: Chapter 20.14 and 15; Chapter 24: This is a challenging chapter, pay attention!

We’re going to skip over the overview chapter of anatomy and physiology (feel free to skim Chapter 20) but we will focus on one major concept within anatomy and physiology before we dive into immunity. Read Chapter 20.14 and 20.15:

Q1. Define homeostasis and give an example: Homeostasis is the steady state of body functioning; it is a state of equilibrium characterized by a dynamic interplay between outside forces that tend to change an organism’s internal environment. An example would be the regulation of body temperature.

Q2. Distinguish negative from positive feedback and give examples. 1. Negative feedback: a form of regulation in which the accumulation of an end product slows that process down. Example: the process that regulates the level of glucose in the blood 2. Positive feedback: regulation by which the accumulation of an end product of a process speeds up that process. Example: giving birth (release of oxytocin) or forming a blood clot to control bleeding from a wound

Q3. Explain how negative feedback affects your ability to not overheat and to not become too cold. Negative feedback and homeostasis go hand in hand, as homeostasis is a dynamic state in which outside forces and internal environments tend to interact. This control mechanism of homeostasis reduces and reserves change in the internal environment by making sure you do not heat up too much or cool down too much, so that you can maintain a steady body temperature.

Q4. We’ll be thinking about sleep as a model of homeostasis. One great example of homeostasis is sleep. We can feel when we are out of balance with this one. And it affects our immune system too. Because sleep is such an important component of wellness overlooked during the college years, let’s learn a bit about it! Use the link below to read the article: http://www.nytimes.com/2014/01/12/opinion/sunday/goodnight-sleep-clean.html?_r=0 “Goodnight. Sleep Clean.” New York Times By MARIA KONNIKOVAJAN. 11, 2014

Use an analogy with trash to explain the value of sleep and the potential problems with too little sleep. As your body sleeps, your brain actively becomes a janitor. It has the responsibility of clearing out all of the junk that has accumulated from a day’s worth of tasks. The article states that the lymphatic system aids in cleaning out the body, and the brain is similar to the body because it is too busy to recycle. Some detrimental effects that can result from too little sleep, along with the accumulation of trash pile up could be neurodegenerative diseases like Alzhiemer’s and Parkinson’s.

How has sleep changed over the past decade for the public? Sleep has changed significantly over the past decade because people have become increasingly more sleep-deprived as they continue to work long, taxing hours, become more stressed, etc. Society has even resorted to synthetic forms of sleep, including sleeping pills to help them get enough rest (which is not as effective)

Chapter 24: The Immune System Q4. True or false (and explain your answer). Only girls need to get the HPV vaccine. False; experts say that both and girls be vaccinated when they are 11-12 years old.

Q6. Is an immune system unique to humans? No, all animals contain an immune system. An immune system is the body’s system of defenses against agents that cause disease. List some external barriers of the innate system that prevent infection: 1. Barriers

2. Inflammatory response 3. Natural killer cells

Q7. Describe these cells of the innate system: Neutrophils- The most abundant type of white blood cell; functions in innate immunity as a type of phagocyte cell that tends to self-destruct as it destroys foreign invaders

Macrophages- A large phagocytic white blood cell that functions in innate immunity by destroying microbes and in adaptive immunity as an antigen presenting cell.

Q8. What does activation of the complement system do to invading pathogens? It can enhance phagocytosis of invading pathogens, cause the rupture of pathogens, and amplify the inflammatory response.

Q9. Why is widening (dilation) and leakiness of blood vessels useful for an inflammatory response by the immune system? What chemical is responsible for dilation/leakiness of blood vessels? The main function of the inflammatory response is to disinfect and clean injured tissues. Histamine is responsible for leakiness of blood vessels.

Q10. What are some clues that there is a systemic inflammatory process (infection) taking place in the body? Elevated white cell count and fevers.

Q11. Why is the inflammatory response considered part of the innate immune system?

Damage to tissue triggers the inflammatory response which allows the body to disinfect and clean injured tissues.

Q12. Figure 24.3 gives an overview of ways that innate and adaptive immunity are different, what are these? Innate: - Innate external barriers: skin, environment, secretions - Innate internal defenses: phagocytic cells, natural killer cells, defensive proteins, inflammatory response - Rapid response - Recognizes broad ranges of pathogens - No memory Adaptive: - Lymphocytes - Defense against pathogens in body fluids - Defense against pathogens inside body cells - Slower response - Only recognizes specific pathogens - Has memory Q13. Why does adaptive immunity differ from individual to individual?

Adaptive immunity is acquired in which a vertebrae-specific defense is activated only after exposure to an antigen. It varies from individual to individual based on what pathogens you have previously been exposed to.

Q14.Define the following terms: a. Antigen: A foreign molecule that elicits an adaptive immune response. Immune system attacks this with an increase in number of cells that either attack the invader or produce antibodies. b. Antibody: A protein dissolved in blood plasma that attaches to a specific kind of antigen and helps counter its effects. It is an immune protein. c. Epitope: The part of an antigen molecule to which an antibody attaches itself. d. Lymphocytes: A type of white blood cell that is chiefly responsible for adaptive immune response and is found mostly in lymphatic system. If you have swollen lymph nodes, what is likely going on in your body?

Your body is likely fighting an infection. Q15. Two important features of adaptive immunity are listed, what do these mean? a. Adaptive immunity is highly specific: (be sure to use the words antigen and antibody in your descriptions) Because it depends on what antigens your body has been exposed to. If you have been exposed to a certain antigen, your body will eventually develop antibodies to fight off that infection.

b. Adaptive immunity has memory: When immune system is exposed to a new antigen, the specifics of that antigen are memorized to ensure prevention of the disease.

Q16. What are two ways to achieve active immunity to a specific pathogen (such as chicken pox virus): Vaccinations and exposure.

Q17. How is passive immunity different? Have you ever been passively immunized? What are some examples? Passive immunity are antibodies given to a person to ensure prevention of a disease or to treat one. It can be passed down from mother to child through the placenta and breast milk. Q18. Now we get into the “nuts and bolts” for adaptive immunity. a. What are the two types of lymphocytes? Discuss how they recognize such a huge diversity of antigens:

B Cells - Type of lymphocyte that completes its development in the bone marrow - Responsible for humoral immune response

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Bind to antigens directly

T Cells - Lymphocytes that migrate to the thymus - Effector cells for the cell-mediate immune response - Helper cells required for both humoral and cell-meditated adaptive responses - Need an additional step for recognition

b. Compare and contrast the two parts of the “dual defense” of adaptive immunity: humoral: branch of adaptive immunity that activated B cells and leads to antibody production.

cell-mediated defenses: the branch of adaptive immunity that involves activation of cytotoxic T cells

Q19. True or false: (explain) an antigen can be recognized by more than one type of antigen receptor. False; B and T cells are used by immune system as a huge army of soldiers. Q20. True or false (explain): An antigen is the same thing as a bacterium. False; antigens are molecules which may be chemical components of the pathogen’s surface. Q21. Envision that a particular virus, chicken pox, has just entered the body. We might need millions of B and T cells to combat this virus. But, we only have a few B cells and a few T cells currently in the body that can recognize chicken pox virus. In a brief description, what has to happen? When the body encounters an antigen, it attracts B and T lymphocytes. However, one particular antigen interacts with only a few lymphocytes that have receptors specific to the antigen. Lymphocytes proliferate once the antigen is activated and form thousands of cells selected to recognize that specific antigen. Now, let’s detail this description focusing on how B cells expand to make antibodies specific to chicken pox virus in the primary humoral response. Describe the figure of 24.7

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First time antigen is swept into lymph node and binded to a B cell B cell is activated Some B cells differentiate to memory cells and others become effector cells Memory cells remain in lymph nodes They activate immune response and last for decades Effector cells secrete antibodies into blood and lymph Antigens bound by antibodies are marked for destruction

Q22. Effector cells can be B or T cells, yet in the clonal expansion of B cells, effector cells that produce antibodies are specifically known as plasma cells.

Q23. Memory cells can be B or T cells once clonal expansion has occurred. What is the role of memory B cells in the humoral response? How do they become important when the chicken pox virus in encountered a second time? Memory B cells stay inside lymph nodes to recognize recurring infections. They can last for decades. They are important in chicken pox because if there is a recurring case, it is a lot less severe than the first time. Q24. Using figure 24.8, describe differences in the speed and strength of the primary and secondary humoral response. Be sure to start by looking on the X and the Y axis. Primary response: it takes several days for lymphocytes to become activated by antigen X and form clones (illness period) Second exposure: a much quicker process and produces much higher levels of antibodies. Q25. Antibodies themselves do not kill pathogens. How do they help to kill pathogens though? They combine with pathogens to form an antigen-antibody complex. Once the pathogen is marked, other immune components are brought in to help destroy the pathogen. Q26. Explain the concept of herd immunity and what happens when not enough people in a population are vaccinated. Herd immunity is the protection of a vaccinated community. It is the rationale behind state-mandated vaccinations for children in public schools.

Q27. Examine figure 24.12B. What type of cell is responsible for activating both the B cells (humoral response) and the cytotoxic T cells (cell mediated response) of the adaptive immune response? Activated T helper cells. Q28. What type of cell does the helper T cell have to interact with to become activated? Antigen-presenting cell.

Q30. What does a cytotoxic T cell do destroy infected body cells? -

Bind to an infected cell Synthesizes several toxic proteins Perforin is discharged from T cell Infected cells die and mark the released antigens for disposal Cytotoxic T cell may move on to destroy other cells infected with same pathogen

Q31. Briefly describe how loss of helper T cells (as in HIV/AIDS) causes a decreased ability to fight infection.

T cells are attacked by HIV due to its depletion of the number of T cells, both the cell-mediated and humoral immune responses are severely impaired. This causes the body’s inability to fight infections....